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xiaochenwumin

各位大侠：我在做一个钢筋混凝土的简支梁计算，考虑材料的非线性。这个是我的命令流
!模型采用单位统一为 mm  N  g
finish
/clear
/config,nres,2000               !设置结果的荷载子步数最大为2000
/filname,jian zhi liang
/title,concrete
/prep7

pi=acos(-1)                     !定义参数π

et,1,solid65,,,,,,,1            !混凝土
et,2,link8                      !钢筋


r,1
r,2,0.25*pi*20*20
r,3,0.25*pi*10*10
r,4,0.25*pi*8*8


mp,ex,1,11305              !弹性模量
mp,ex,2,2.0e5



mp,prxy,1,0.2
mp,prxy,2,0.3                   !泊松比



fc=11.9 $ ft=1.27              !混凝土的抗压强度和抗拉强度

tb,concr,1
tbdata,,0.5,0.95,ft,-1         !定义混凝土材料及相关参数，关闭压碎
tb,miso,1,,11                  !定义混凝土应力应变曲线


tbpt,,0.0002,fc*0.19
tbpt,,0.0004,fc*0.36
tbpt,,0.0006,fc*0.51
tbpt,,0.0008,fc*0.64
tbpt,,0.0010,fc*0.75
tbpt,,0.0012,fc*0.84
tbpt,,0.0014,fc*0.91
tbpt,,0.0016,fc*0.96
tbpt,,0.0018,fc*0.99
tbpt,,0.0020,fc
tbpt,,0.0033,fc


tb,biso,2
tbdata,,300,0

!建立钢筋混凝土模型

k,1,0,300,125
k,2,0,300,-125
k,3,0,-300,125
k,4,0,-300,-125
k,5,6000,300,125
k,6,6000,300,-125
k,7,6000,-300,125
k,8,6000,-300,-125



v,1,2,4,3,5,6,8,7

!箍筋

wprota,0,0,90
*do,i,1,29
wpoff,0,0,200
vsbw,all
*enddo


wpave,0
wprota,0,90,0
wpoff,0,0,-270
vsbw,all

wpoff,0,0,535
vsbw,all

wprota,0,0,90
vsbw,all
wpoff,0,0,-90
vsbw,all
wpoff,0,0,180
vsbw,all
wpave,0,0,0


!网格划分
!钢筋网格划分

lplot
lsel,s,loc,y,-265
lsel,r,loc,z,90
latt,2,2,2
esize,50
lmesh,all

allsel
lplot
lsel,s,loc,y,-265
lsel,r,loc,z,0
latt,2,2,2
esize,50
lmesh,all

allsel
lplot
lsel,s,loc,y,-265
lsel,r,loc,z,-90
latt,2,2,2
esize,50
lmesh,all


allsel
lplot
lsel,s,loc,y,270
lsel,r,loc,z,90
latt,2,3,2
esize,50
lmesh,all


allsel
lplot
lsel,s,loc,y,270
lsel,r,loc,z,-90
latt,2,3,2
esize,50
lmesh,all

allsel
lplot
lsel,s,loc,y,-265,270
lsel,r,loc,z,-90,90
lsel,u,loc,z,0
lsel,u,mat,,2
latt,2,4,2
esize,50
lmesh,all


!混凝土网格划分

allsel
vplot
vatt,1,1,1
mshape,0,3d
mshkey,1
esize,50
vmesh,all


nummrg,all
numcmp,all   

!施加约束

allsel
nplot
nsel,s,loc,x,0
d,all,uy,,,,,uz,ux
allsel
nsel,s,loc,x,6000
d,all,uy,,,,,uz
allsel
eplot


!施加荷载

aplot
asel,s,loc,y,300
sfa,all,,pres,0.088
sftran
allsel
eplot

/solu
antype,static
nsubst,100
outres,all,all
autos,on
neqit,50             !设置子步迭代次数为50
cnvtol,u,,0.015      !采用位移收敛准则，且收敛误差为1.5%
solve
可是在求解的时候出现了这样的错误
The value of UY at node 3771is1.031041091E13.It is greater than the current limit of 1000000.This generally indicates rigid body motion as a result of an unconstrained model. Verify   that your model si properly constrained.


我检查了约束没有问题，而且我同学同样用的这个命令流只是截面尺寸变了他的确没有出现这个错误，大家可不可以告诉我为什么啊？？？？？求救啊！！要交作业了！！！！